Despite its pretensions, this fire-snorting municipal tell-all packs less punch on TV than an average Homicide episode. Cowritten by a former New York political insider — Ken Lipper, a deputy mayor under Ed Koch — City Hall is both redolent with detail and too damn pat. John Cusack, saddled with a corn-pone accent, is likable as the heroic deputy to Mayor John Pappas (Al Pacino), but the script absurdly makes him a Woodward-Bernstein composite as he trails a shooting to the Mob and beyond. Other performances vary: Bridget Fonda seems a wan afterthought as Cusack’s legal-eagle love interest, but Danny Aiello brings a tenderloin poignancy to the role of a kingmaker who owes too many favors. The fine, regal Pacino comes off as a modern La Guardia — until he gives a funeral oration that’s the fruitiest example yet of his recent penchant for overacting. B-